Hypothyroidism may result from a variety of causes, including Hashimoto thyroiditis, iodine deficiency, and certain medications. It is also associated with Down syndrome, Turner syndrome, and other autoimmune disorders. Hypothyroidism can contribute to the development and progression of various cardiovascular diseases. The deficiency of thyroid hormones leads to a broad spectrum of clinical signs and symptoms. All patients with suspected hypothyroidism should undergo serum thyroid-stimulating hormone (TSH) and serum free T4 testing. Measurement of thyroid peroxidase antibodies can aid in predicting the progression to overt hypothyroidism. Levothyroxine supplementation remains the treatment of choice. In cases of subclinical hypothyroidism, treatment decisions should be individualized, taking into account the patient's age, clinical symptoms, risk factors, and laboratory findings. Patients should be thoroughly counselled regarding their diagnosis, the selected treatment approach, and the importance of long-term monitoring and follow-up.